Electrodeionization (EDI), also known as electrochemical ion-exchange, is an advanced ion-exchange technology that combines the advantages of ion-exchange and electrodialysis. In an electrodeionization process, ion exchange resins are sequestered in dilute compartments to increase ionic conductivity, so that even with very dilute ionic feed (e.g., about 10−5N), a stable operation with higher ion separation flux and lower energy consumption than electrodialysis becomes possible. EDI technology is presently used to make deionized water for boiler feed and high purity and industrial water applications. However, there are also other uses and potential uses of such technology for processing organic product streams in a variety of industries. Some of these technologies have been touched on by patents and patent applications filed on behalf of Argonne National Laboratory (ANL) such as, for example U.S. Pat. No. 6,797,140, U.S. Pat. No. 6,495,014, and U.S. Pat. No. 8,007,647, the entire disclosures of each of these references being herein incorporated by reference.
In many fermentation and enzymatic processes a high (e.g., millimolar) concentration of medium components must be maintained. Common examples are monovalent and divalent cations and anions that provide an appropriate required ionic environment for optimum activity of microorganisms and enzymes. These monovalent and divalent cations and anions are identified as counter-ions hereinafter. The concentrations of the counter-ions in the fermentation reaction medium should be maintained within a predetermined range to ensure optimum reaction conditions. Diminishing counter-ion concentration in the fermentation broth or reaction medium can be a serious problem, because replacement of the counter-ions in a flow-through system would be expensive and would prohibitively increase the cost of obtaining the fermentation product. There is an ongoing need for new, more efficient processes for producing organic acids such as succinic acid. The present invention addresses this need.